Controlled peaking trasformer



March 5, 1946 H. KLEMPERER 2,395,831

CONTROLLED PEAKING TRANSFORMER Filed Aug. 2, 1940 4 Sheets-Sheet 1 Fuel.

VOLTAGE 0N con. 3

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HANs' KLEMPERER,

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SATURATION F'Lux or L56 4 Vo LTAG E o F Con. 7AM!) 5 u PEAK VOLTAGEfllLovoLTs.

March 5, 1946. KLEMPERER 2,395,881

CONTROLLED PEAKING TRANSFORMER Filed Aug. 2, 1940 4 Sheets-Sheet 2 FIG.5.

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March 5, 1946. H. KLEMPERER CONTROLLED PEAKING TRANSFORMER Filed Aug. 2.1940 4 Sheets-Sheet 3 HUN 7/////// numu 'NVENTOR HANS KLEMPERER,

March 5, 1946. H. KLEMPERER CONTROLLED PEAKING TRANSFORMER Filed Aug. 2,1940 4 Sheets-Sheet 4 FIG."

d 1"6 FIG. 12. 90 FIG. l3.

, I TOTAL VOLTAGE n f AcRoss Cows I a VOLTAGE oF 601154962 INVENTOR.HANS KLEMPERER,

Patented Mar. 5, 1946 UNITED STATES PATENT OFFICE CONTROLLED PEAKINGTRANSFORMER Hans Klemperer, Belmont, Mass, assignor to RaytheonManufacturing Company, Newton, Mass., a corporation of DelawareApplication August 2, 1940, Serial No. 349,785 (Cl. 171 119) 3 Claims.

This invention relates to controlled peaking transformers in whichalternating voltages of sine wave form are converted into peaked wavesof controllable magnitude. Heretofore, the control of the magnitude ofthe peaking output waves of such transformers has required a considerablamount of control power.

An object of this invention is to produce a peaking transformer .inwhich the magnitude of the peaked output voltage may be varied through awide range in response to a relatively small controlling factor.

Another object of this invention is to produce such variation by usingsmall direct currents.

A still further object of this invention is to produce such variation bythe use of movable magnetic means.

The foregoing and other objects of this invention will be bestunderstood from the following description of exemplifications thereof,reference being had to the accompanying drawings wherein: I

Fig. 1 is a diagrammatic representation of a peaking transformerembodying my invention;

Figs. 2, 2a, 3, 3a, and 4 are curves representing the mode of operationof the arrangement shown in Fig. 1;

Fig. 5 is a diagrammatic representation of a modification of thearrangement shown in Fig. 1;

Figs. 6, 6a, and 6b are curves representing the mode of operation of thearrangement shown in Fig.

Fig. 7 is a diagrammatic representation of a circuit in which theembodiment illustrated in Fig. 1 may be used;

Fig. 8 is a representation of a modified form of my invention using amovablemagnetic control means;

Fig. 9 represents another embodiment of my invention in which motordriven movable magnet control means are utilized;

Fig. 10 is a top view of the device shown in Fig. 9;

Fig. 11 is a representation of a still further embodiment of myinvention; and

Figs. 12, 13, and 13a ar curves illustrating the mode of operation ofthe embodiment shown in Fig. 11. t

The embodiment shown in Fig. 1 consists of a core member I made ofsuitable magnetic material such a iron. Said core is provided with acentral leg 2 upon which the input winding 3 is wound. The winding 3 isadapted to be energized from some suitable source of alteinating currentusually of substantially sine wave form. On one side of the central leg2 is located a saturable leg 4 preferably made of a material of highmagnetic permeability such as Permalloy steel. The saturable leg 4 ismade with two side leg portions 5 and 6 upon which output coil l and 8respectively are wound. The peaked output voltages are generated inthese coils l and 8, which, in the arrangement shown in Fig. 1, areconnected in series. In order to introduce saturating flux, 9, leg 9 isprovided extending from between the leg portions 5 and 6 to the centralportion of the central leg 2. .A coil I0 is wound upon the leg 9 and isadapted to be supplied with direct current for the purpose ofintroducing sufficient direct current flux into the leg portions 5 and 6to saturate them. The leg 9 is also preferably surrounded by ashort-circuited loop II which tends to keep alternating flux out of theleg 9. A pair of side legs l2 and I3 connect the outer ends of the legportions 5 and 6 to- I the outer ends of the central leg 2 and extendbeyond said central leg to a lower leg I4 which is adapted to carry thealternating current leakage flux. The lower leg I 4 is provided with anair gap I5 which introduces magnetic resistance into the magneticcircuit of which the leg I4 is a part, and also serves to prevent theleg [4 from becoming saturated.

The operation of such an arrangement as is shown in Fig. 1 may beunderstood more clearly by referring to the curves in Figs. 2, 2a, 3,3a, and 4. In these figures, a represents voltage applied to theexciting or input coil 3; b and 0 represent the positive and negativevalues of flux at which the leg 4 and its side leg portions 5 and 6become saturated. Figs. 2 and 2a represent the operation without anyappreciable direct currents supplied to the coil [0. Under theseconditions, the magnetomotive force applied to the leg 4, represented byd varies about the zero flux axis and lags the voltage a bysubstantially degrees. Since the flux in the legs 5 and 5 changes onlyas the magnetomotive force d causes said flux to pass between the twosaturating values, voltages are generated in the coils 1 and 8 onlyduring this period. Furthermore, the voltages which are generated inthese coils are in phase. Therefore, in Fig. 2a the voltage which isgenerated in each of the coils l and 8 is represented by h and sincethese two coils are in series, the total output voltage across thesecoils may be represented by i which is double h. If the coil I0 issupplied with sufficient direct current to impress upon the leg 5 a biamagnetomotive force represented by j in Fig. 3 and to impress a biasmagnetomotive force on leg 0 as represented by g in Fig. 3, the totaloutput voltage i is substantially decreased as represented in Fig. 3a.Under these conditions, the alternating magnetomotive force d5 which isapplied by the coil 3 to the leg 5 varies about the bias 1 as an axisand lags the voltage a by substantially 90 degrees as before. Thealternatingv magnetomotive force d6 applied to the leg 8 by the coil 3varies about the bias 9 as an axis and likewise lags the voltage a bysubstantially 90 degrees. Under these conditions, the flux e! of the leg5 which passes through the coil 1 is advanced in phase and the flux e8of the leg 6 which passes through the coil 8 is delayed in phase.

Therefore, as shown in Fig. 3a, th voltages h! and k8 generated in thecoils l and 8 respectively are no longer in phase but are delayed andadvanced respectively to the same degree as the fluxes which generatethem. Therefore the total output voltage i which still is the sum of thevoltages of the coils i and 8 is reduced considerably in amplitude, witha somewhat increased width. However, in most applications to which suchpeaking transformers are put, the amplitude of the peaked output wave isthe significant or controlling factor and therefore the widening of thevoltage peak is non-objectionable.

It will be seen from the foregoing that by properly selecting theconstants of the system, a relatively small value of direct currentsupplied to the coil Hiwill vary the magnitude of the peaked outputvoltage wave to a comparatively great degree. For example, thecontrolling characteristics of such a system may be represented in Fig.4 in which milliamperes of direct current bias supplied to the coil inmay be plotted along the horizontal axis and the peakoutput voltage inkilovolts may be plotted along the vertical axis. The resultantvariations may be represented by the curve It in Fig. 4. Of course, itis to be understood that the comparative values as represented in Fig. 4may be varied over very wide limits by properly selecting the constantsof the system as shown in Fig. 1.

Instead of connecting the coils l and 8 so that their voltages add,these coils can be connected so that their voltages oppose each other asrepresented in Fig. 5. In such an arrangement, when no direct current issupplied to the coil in, the voltages of the coils 1 and 8 are equal andopposite, and the output voltage haszero amplitude. When the coil I0 issupplied with direct current, the separation as represented in Figs. 6,6a, and 6b ensues. In these figures, the reference numerals'have thesame significance as in Figs. 2-4. As previously explained, the voltagesh! and 728 are no longer in phase with each other, but are displaced toa degree which by proper design may be that as represented in Fig. 6a.The output voltage from the coils l and 8 under these conditions,consists of a succession of such peaked alternations as is representedin Fig. 6a. If it is desired to have each impulse uni-directional, arectifying bridge l6 may be connected to the output of the coils 1 and 8as represented in Fig. 5. Under these conditions, the two voltage peaksof the alternation represented in Fig. 6a are made uni-directional,giving the resulting output impulse as represented in Fig. 61 Underthese conditions, the voltage appearing at the output of the rectifyingbridge l8 consists of a succession of such double peaked impulses asshown in Fig. 6b.

The peaked output voltage of this invention may be applied to anydesired use. One of these uses is in connection with the control of anelectrical space discharge tube. Such an application is represented inFig. 7 in which electronic tube I1 is shown provided with an anode IIand a cathode l8, preferably of thermionic type. The tube is providedwith a control grid 20 which permits a discharge to start between thecathode and anode, when the grid is supplied with a starting voltageimpulse. The tube is adapted to be supplied with alternating currentfrom a pair of terminals 2| and 23. The terminal 2| is connected througha load 22 to the anode IS. The terminal 23 is connected directly to thecathode ID. The peaked output voltage of the coils I and I is connectedbetween the cathode l9 andthe grid 20. It is usually desirable in suchinstances to control the phase at which the igniting impulse is suppliedto the igniting electrode. For this reason, a controllable phase shiftdevice 24 of any suitable type is energized from the terminals 2| and 23and has its output connected to the energizing coil 3 of the peakingtransformer. As previously indicated, the amount of direct current powernecessary for controlling the output of such a peaking transformer isrelatively slight, and may be supplied in the arrangement shown in Fig.7 from a thermocouple 25. The device 25, in some instances, may consistof a photo-electric cell or any other desired source of direct current.

The system illustrated in Fig. 7 operates as described in Fig. 1 so asto supply peaked voltages to the grid 20. In absence of energization ofthe coil in from the thermocouple 25, the amplitude of the peak voltagethus supplied is suflicient to initiate the discharge during eachconducting half cycle of the alternate voltage applying to the tube H.The point at which this firing voltage impulse is supplied to theelectrode 20 is determined by the setting of the phase shift device 24.If, however, the thermocouple 25 is heated so as to operate the coil IIIwith direct current, the output voltage of the coils I and 8 is reducedto such an extent that it is no longer suflicient in magniture to ignitethe tube l1 and thus the tube stops conducting current. It will be seentherefore, that the tube I! which may deliver large amounts of power tothe load 22, can be energized and deenergized at will by the relativelysmall amount 01 energy delivered from the thermocouple 25.

Instead of utilizing direct current for supplying the saturatingmagnetomotive force, such saturating magnetomotive force can be suppliedand controlled in other ways. For example, a movable magnet may beutilized for this purpose as illustrated in Fig. 8. In this figure,where the elements are identical with those shown in Fig. 1, the samereference numerals are applied thereto. In Fig. 8 the central leg ofFig. l is replaced by a pair of pole pieces 26 and 21 between which anarmature 28 is rotatably mounted. The armature is made in the form of apermanent magnet although if desired, it could be in the form of anelectromagnet. A short circuited turn 29 corresponding to the shortcircuited turn ll of Fig. l is provided on one of the pole pieces. Thearmature 28 is mounted upon a rotatable shaft 10 provided "with somesuitable means for rotating it such as a crank 3!.

The operation of the arrangement shown in Fig. 8 is identical with thatdescribed in connection with Figs. 1-4. However, in connection with Fig.8, the magnetomotive force which is supplied as a bias to the legs 5 and6 varies with the angular relationship between the pole pieces 28 and 21and the armatur 28. Thus the operation of the device shown in Fig. 8with the armature 28 in line with the pole pieces can be between thepole pieces 26 and 21.

21 can be represented by Figs. 2 and 2a in which,

an increase in the amplitude of the output voltageis secured. Fig. 4also can represent the operating characteristics of the arrangementshown in Fig. 8 if the angular displacement from vertical position ofthe magnetic armature 28 is plotted along the horizontal axis.

Instead of utilizing a single movable magnet' as shown in Fig. 8 aplurality of movable mag- I nets can be utilized as illustrated in Figs.9 and 10. Here likewise, where elements are identical with those in Fig.8, the same reference numeral are applied; In Figs. 9 and 10, the singlemovable magnet of Fig. 8 is replaced by a plurality of magnets 32mounted on a wheel 33 which is rotatably supported on a shaft 34. Theshaft may be rotated by any suitable means which preferably consists'ofa synchronous motor 35.

If the arrangement shown in Figs. 9 and 10 applied, for example, to asystem as shown in Fig. 7, the synchronous motor 35 can be driven fromthe same source of alternating current as that which energizes the coil3. Under these conditions, the constants of the system and the number ofmagnets 32 can be so selected that during each cycle, one of the magnets32 passes These can be so adjusted that they are in alignment duringeach conducting half cycle applied to the tube ll.

Under these conditions, the amplitude of the output voltage of the coils1 and 8 is maintained at a reduced value so that the tube i1 does notfire. In order to cause the tube I1 to fire the magnets 32 are maderemovable. Therefore, as one of the magnets 32 is removed, the tube IIwill fire and conduct current during the'cycle corresponding to theremoved magnet. By properly selecting magnets 32 for removal, anydesired sequence of operationof the tube I! or any other devicecontrolled by the coils I and 8 may be produced.

If, instead of having the voltage of the coils I and 8 add, thearrangement of these coils as represented in Fig. is utilized, theopposite effect is produced, namely the tube i1 fires whenever one ofthe magnets 32 is in alignment with its associated pole pieces and thetube is prevented from firing merely by removing one or more of themagnets 32.

In some cases, it may not be desirable to have each of the elements 32in itself a permanent magnet, but rather a magnetic armature member.Under these conditions a D. C. exciting coil 36 can be mounted on on ofthe pole pieces 21 and the usual short circuited loop 31 may be mountedon the other pole piece 25. The operation under these conditions will beexactly the same a if the members 32 were themselves permanent magnets.A similar variation could be introduced into Fig. 8.

Another mode of operation of the arrangement shown in Fig. 9 could be tohave the coil 36 excited with a sufficient magnitude of current toproduce an initial saturation of the legs 5 and 6 so as to produce aninitial phase displacement between the voltages of coils l and 8. If,under these conditions, the members 32 are in the form of permanentmagnets polarized so as to. oppose the magnetization of the coil 36,each of the magnets 32 as it comes into alignment with the poles 26 and21 will cancel the magnetomotive force of the coil 38 and eliminate theinitial phase displacement between said voltages. Here, likewise, aseach magnet 32 comes into alignment with the pole pieces 26 and 21, theamplitude of the output voltage across the coils 1 and 8 will beincreased and as said magnet passes out of such alignment the amplitudof the output voltage will be decreased.

The relative values of the maximum and minimum amplitudes of outputvoltage of peaking transformers constructed in accordance with myinvention may be increased by utilizing somewhat more complex formsthereof. Anhrrangement of this kind is shown in Fig. 11. Here likewise,where elements are identical with those shown in Fig. 1, the samereference numerals are applied. In Fig. 11 the central direct currentbias leg is replaced by a central leg 38 subdivided at its upper endinto three smaller legs 39, 40. and M. The legs 33, 40, and 4| may beprovided with short circuited rings 42, 43, and 44 respectively. Thesaturable leg 4 is subdivided into four sections, 45, 46, 41 and 48instead of the two sections of Fig. 1. In Fig. 11, the saturable legsections 45-43 are provided with coils 49, 50, 5| and 52 respectively.The D. C. saturating coil Ill is placed upon the main leg 38.

The operation of the device shown in Fig. 11 may be best understood byreferring to Figs. l2, l3, and 13a. Here likewise, the same referenceletters are applied as in the case of Figs. 2 and 3a, where the purvesare identical. In Fig. 12 m represents the voltage of one of the coils45-52. Therefore the total voltage 1: across all of the coils 45-52 isfour times the value m. In Fig. 13

p, r, s, and t represent the bias magnetomotive forces on legs 46, 45,48, and 4! respectively. Due to the fact that the resultantmagnetomotive forces applied to the legs 4548 respectively vary aboutthe bias fluxes pt as axes, the voltages generated in the coils 49-52are displaced in phase with respect to each other as explained inconnection with Fig. l. Thisrelative displacement between these voltagesis represented in Fig. 13a. The summation of these displaced voltages'is also represented in Fig. 13a by n. A comparison of the peak amplitudeof the voltages of Figs. 12 and 13a shows that in the arrangement ofFig. 11 a greater change in the amplitude of the output voltage isobtainable by this arrangement than by the previously describedembodiments.

Of course, it is to be understood that this invention is not limited tothe particular details as described above as many equivalents willsugest themselves to those skilled in the art. For example, instead ofutilizing direct current for the saturating magnetomotive force,alternating currents of various kinds could be utilized in particularembodiments. Also, different features of each embodiment could beincorporated into each of the other embodiments. Various otherapplications of the principles enunciated herein could be utilized bypersons skilled in the art. It is accordingly desired that the appendedclaims be given a broad interpretation commensurate with the scope ofthe invention within the art.

What is claimed is:

1. A peaking transformer system comprising a magnetic core havingprimary and secondary portions spaced from each other, said secondaryportion being divided into a plurality of separate parts and being morereadily saturable than said primary portion, a primary winding on saidprimary portion, means for exciting said primary winding with aperiodically varying voltage to set up a periodically varying primaryflux, said core having a leakage path portion to bypass a portion ofsaid primary flux away from said secondary portion, a separate5800131181? winding CD11 on ferent directions in diflerent secondaryparts.

with respect to the varying flux set up in said secondary parts by saidprimary winding, and a short-circuited turn on said bias flux leg toimpede the passage of primary flux through said bias said primary voltae being sufllcient to cause saturation of said secondary portion.

2. A peaking transformer system comprising a magnetic core havingprimary and secondary portions spaced from each other, said secondaryportion being divided into a plurality of separate parts and being morereadily saturable than said primary portion, a primary winding on saidprimary portion, means for exciting said primary winding with aperiodically varying voltage to set up a periodically varying primaryflux, said core having a leakage path portion to bypass a portion ofsaid primary .iiux away from said secondary portion, a separatesecondary winding coil on each of said secondary parts, said secondarycoils being connected in series, the resultant voltage of said secondarycoils being impressed upon a common load device, said core also having abias flux leg for passing a unidirectional bias flux in differentdirections in different secondary parts with respect to the varying fluxset up in and secondary parts by said primary winding, said bias fluxleg being subdivided at one end into a plurality oi sub-legs, each ofsaid sub-legs extending to a point intermediate two of said separatesecondary parts, said primary voltage being suflicient to causesaturation of said secondary portion.

3. A peaking transformer system comprising a magnetic core havingprimary and secondary portions spaced from each other, said secondaryportion being divided into a plurality of separate parts and being morereadily saturable than said primary portion, a primary winding on saidprimary portion, means for exciting said primary winding with aperiodically varying voltage to set up a periodically varying primarflux, said core having a leakage path portion to bypass a portion ofsaid primary flux away from said secondary portion, a separate secondarywinding coil on each 01 said secondary parts, said secondary coils beingconnected in series, the resultant voltage of said secondary coils beingimpressed upon a common load device, said core also having a bias fluxleg excited by a coil supplied with direct current for passing aunidirectional bias flux through said secondary parts, a short-circuitedturn on said bias flux leg to impede the passage of primary flux throughsaid bias leg, said primary voltage being sufllcient to cause saturationof said secondary portion, of said primary winding and said coil on saidbias flux leg, one sending flux all in the same direction through saidseparate secondary parts and the other sendin flux in diiferentdirections through said separate secondary parts.

HANS KLEMPERER.

